CN107328986B - Double-sampling double-demodulation fault warning device and method for optical fiber current transformer - Google Patents
Double-sampling double-demodulation fault warning device and method for optical fiber current transformer Download PDFInfo
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Abstract
The invention discloses a double-sampling double-demodulation fault warning device and method for an optical fiber current transformer. Two paths of AD in the device sample a detector signal in parallel, sampling data are simultaneously and independently demodulated through a demodulation module, current signals obtained by demodulation are added and averaged, then the current signals are applied to a Y waveguide modulator through a DA conversion circuit to realize closed-loop control, and simultaneously the current signals obtained by demodulation are respectively output to realize the dual configuration requirement of power application; comparing and judging data obtained by alternately sampling two ADs in the same modulation amplitude value to give an AD fault alarm signal; and comparing current signals obtained by simultaneously and independently demodulating the two AD sampling data to give out fault alarm signals of the demodulation module. The invention realizes the functions of dual configuration output, core devices and fault alarm of the modulation and demodulation module without increasing the complexity of the optical path, and has simple structure, low cost and high intelligence degree.
Description
Technical Field
The invention relates to a double-sampling double-demodulation fault warning device and method for an optical fiber current transformer, and belongs to the field of power equipment.
Background
The optical fiber current transformer is a key device of an electric power system, is used for measuring the current and providing measurement information for electric energy measurement and control protection, has the advantages of simple insulation, small volume, safety, reliability, digitization, intellectualization, integration of measurement, measurement and protection and the like, is already applied in batches in an intelligent transformer substation and represents the development direction of the transformer. The optical fiber current transformer is based on magneto-optical Faraday effect and ampere loop law, namely polarized light deflects in a magnetic field generated by current, namely the phase is changed, and the deflection angle is in direct proportion to the current. The fiber current transformer converts phase change caused by current into light intensity change by utilizing a reciprocal light path interference principle, light intensity signals are converted into electric signals through a photoelectric detector, then the electric signals are sampled by an AD (analog-digital) module, the signals are demodulated by a demodulation module, the current signals are output after demodulation, bias signals and feedback step waves are generated at the same time, and finally the bias signals and the step waves are superposed and then are jointly applied to a Y waveguide device to complete digital closed-loop control.
The current optical fiber current transformer adopts a single AD sampling and single demodulation method, the output value of the measured current signal is obtained by AD sampling demodulation, and the use requirement can be met when a single set of configuration application of an electric power system is adopted. However, in the application of the new-generation intelligent substation, a user considers the reliability of the substation, performs redundancy design on part of current relay protection configuration, and provides a configuration application standard, and requires that the current transformers for relay protection are doubly configured and subjected to dual-AD sampling, 4 paths of independent sampling protection data are output by the same measuring point, that is, two sets of independent current transformers need to be configured at the same current protection measuring point, each set of transformers need two paths of independent AD sampling and demodulate the independent output protection data, once one AD fails, the other path of AD can also be normally sampled, and protection data are provided.
When current optic fibre current transformer is using, in order to satisfy the configuration requirement, need assemble 4 sets of independent optic fibre current transformer at same measuring point, give 4 way independent protection data, consequently current optic fibre current transformer required cost is higher, the structure installation is inconvenient when carrying out the design of two configuration schemes, is unfavorable for engineering application.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the double-sampling double-demodulation fault warning device and method for the fiber current transformer overcome the defects of the prior art, and achieve the double-configuration output and core device and modulation and demodulation module fault warning functions under the condition that the complexity of an optical path is not increased.
The technical solution of the invention is as follows: the utility model provides a two demodulation fault alarm device of double sampling for fiber current transformer, the device includes two AD modules, data processing module, current contrast output module, wherein:
the two AD modules independently sample voltage signals output by the photoelectric detector of the optical fiber current transformer under the control of a sampling clock to obtain first AD sampling data and second AD sampling data, and output the first AD sampling data and the second AD sampling data to the data processing module;
the data processing module generates a clock signal and sends the clock signal to the AD module and the DA conversion module; according to the intrinsic cycle of the light path, demodulating the first AD sampling data and the second AD sampling data output by the two AD modules respectively to obtain first current data and second current data, and outputting the first current data and the second current data to a current comparison output module; according to the first AD sampling data and the second AD sampling data, fault judgment is carried out on the two AD modules, and a step wave signal is generated according to the fault-free current data; generating a bias signal according to the eigenperiod of the optical path; superposing the step wave signal and the bias signal, converting the signals into analog signals through DA, and feeding the analog signals back to a Y waveguide modulator of the optical fiber current transformer to realize closed-loop control;
the current comparison output module outputs the first current data and the second current data; and meanwhile, the first current data and the second current data are compared respectively, and when the difference between the first current data and the second current data exceeds a preset second threshold value, a fault warning signal of the data processing module is output.
The data processing module comprises a time sequence control module, an AD data comparison module, a demodulation module, a bias modulation wave generation module, a step wave generation module, a signal superposition module and a DA conversion module, wherein:
the time sequence control module generates two working clocks of the AD module and the DA conversion module according to the intrinsic period of the light path and controls the working operation time sequence of the AD device and the DA device;
the AD data comparison module is used for judging faults of the two AD modules according to the first AD sampling data and the second AD sampling data, when the difference between the accumulated average values of the first AD sampling data and the second AD sampling data in the same modulation amplitude exceeds a preset first threshold value, one of the AD modules is considered to have faults, and otherwise, both the two AD modules are considered to have no faults; when the accumulated average value of the sampled data obtained by the same AD module in the same modulation amplitude value is in a preset reasonable range, the AD module is considered to have a fault, otherwise, the AD module is considered to be normal, and an AD module fault alarm signal is sent out;
the demodulation module is used for carrying out parallel processing on the two paths of AD sampling data, independently demodulating the two paths of AD sampling data to obtain first current data and second current data, outputting the current data obtained by adding and averaging the first current data and the second current data to the step wave generation module when the two AD modules have no fault, and outputting the current data to the step wave generation module according to the current data output by the normal AD module when the one AD module has a fault;
the step wave generating module is used for generating a step wave signal according to the current signal input by the demodulation module;
the bias modulation wave generating module generates a bias signal according to the intrinsic cycle of the light path;
the signal superposition module is used for superposing the bias signal and the step wave signal to obtain a feedback signal and outputting the feedback signal to the DA conversion module;
and the DA conversion module is used for DA converting the feedback signal and applying the DA converted feedback signal to a Y waveguide modulator of the optical fiber current transformer to form closed-loop control.
The bias signal is a square wave, a four-state wave or a random four-state wave.
The bias point of the bias signal has a value range of pi/2-pi 3/4.
And in the same modulation amplitude of the optical fiber current transformer, the two AD modules alternately sample at intervals.
The data processing module is realized by adopting a programmable logic device.
The other technical solution of the invention is as follows: a double sampling double demodulation fault warning method for an optical fiber current transformer comprises the following steps:
(1) sampling signals output by the photoelectric detector of the optical fiber current transformer by adopting two independent AD sampling modules to obtain first AD sampling data and second AD sampling data;
(2) judging faults of the two AD modules according to the first AD sampling data and the second AD sampling data, and when the difference between the accumulated average values of the first AD sampling data and the second AD sampling data in the same modulation amplitude exceeds a preset first threshold value, judging that one AD module has faults, otherwise, judging that both the two AD modules have no faults; when the accumulated average value of the sampled data obtained by the same AD module in the same modulation amplitude value is in a preset reasonable range, the AD module is considered to have a fault, otherwise, the AD module is considered to be normal; when both the two AD modules have no fault, generating a step wave signal according to current data obtained by adding and averaging the first current data and the second current data, when one AD module has a fault, generating a step wave signal according to current data output by a normal AD module, and otherwise, generating a step wave signal according to current data of the intrinsic period of the previous light path.
(3) Generating a bias signal according to the intrinsic cycle of the optical path, and entering the step (4);
(4) superposing the step wave signal and the bias signal, converting the signals into analog signals through a DA conversion module, and feeding the analog signals back to a Y waveguide modulator of the optical fiber current transformer;
(5) and outputting the first current data and the second current data, simultaneously comparing the first current data with the second current data respectively, and outputting a data demodulation module fault alarm signal when the difference between the first current data and the second current data exceeds a preset second threshold value.
Compared with the prior art, the invention has the beneficial effects that:
(1) the invention realizes the function of outputting two paths of independent AD sampling protection data by a single set of current transformer, effectively reduces the application cost, and simplifies the application and installation complexity;
(2) the invention realizes the fault judgment and alarm functions of the key electronic device and the core demodulation module, and can effectively avoid the protection misoperation caused by the self fault of the product;
(3) the intelligent degree of the product can be effectively improved, the fault detection cost of the product is reduced, and the line operation inspection working mode is simplified;
(4) the invention has simple structure, low cost and high intelligent degree.
Drawings
FIG. 1 is a schematic diagram of a double sampling double demodulation fault warning method for an optical fiber current transformer;
FIG. 2 is a timing diagram of dual AD sampling according to an embodiment of the present invention;
FIG. 3 is a block diagram of a data processing module according to an embodiment of the present invention.
Detailed Description
The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings.
The invention relates to a double-sampling double-demodulation fault warning method and device for an optical fiber current transformer, wherein the optical fiber current transformer comprises an optical path part and a circuit part, and the schematic diagram is shown in figure 1.
The light path mainly comprises a light source, a coupler A, a coupler B, a photoelectric detector, a Y waveguide modulator, a delay coil, a wave plate, a sensitive ring and a reflector.
The working principle of the light path is as follows: under the action of a driving refrigeration circuit, light emitted by a light source enters an integrated optical device through a coupler A, after phase modulation is carried out on the light by a Y waveguide integrated optical device, two beams of linearly polarized light are output, wherein one beam of light is subjected to phase modulation, the two beams of linearly polarized light enter a delay line along a fast axis and a slow axis of a polarization maintaining optical fiber respectively after passing through a coupler B, the two beams of linearly polarized light are converted into two beams of circularly polarized light through a lambda/4 wave plate, one beam of the circularly polarized light is levorotatory, the other beam of the circularly polarized light enters a sensitive optical fiber of an optical fiber ring for propagation, and under the combined action of the Faraday magneto-optical effect and measured current, the
(wherein N is the number of turns, V is the Vield constant of quartz, and I is the magnitude of current). Two beams of elliptically polarized light are transmitted to the reflector to be reflected and then enter the sensitive optical fiber again, the original left-handed light is changed into right-handed light, the original right-handed light is changed into left-handed light, and the phase is generated under the combined action of the Faraday magneto-optical effect and the measured current againDifference (D)
At this time, the total phase difference becomes
Two bundles of elliptical polarized light carrying current information are converted into linearly polarized light through the lambda/4 wave plate again, the linearly polarized light originally transmitted along the slow axis is converted into linearly polarized light which is transmitted along the fast axis, the linearly polarized light originally transmitted along the slow axis is converted into linearly polarized light which is transmitted along the slow axis, and finally the linearly polarized light returns to the Y waveguide integrated optical device to generate interference, the interference can convert phase transformation into optical power change, the interference light is output by the coupler A to reach the photoelectric detector, the photoelectric detector converts optical signals into electric signals, and the signals can be subjected to signal acquisition and signal demodulation through a circuit after being subjected to preamplification.
The double-sampling double-demodulation fault warning device is a circuit part of the optical fiber current transformer, and comprises two AD modules, a data processing module and a current comparison output module, wherein:
the two AD modules independently sample voltage signals output by the photoelectric detector of the optical fiber current transformer under the control of a sampling clock to obtain first AD sampling data and second AD sampling data, and output the first AD sampling data and the second AD sampling data to the data processing module;
the data processing module generates a clock signal and sends the clock signal to the AD module and the DA conversion module; according to the intrinsic cycle of the light path, demodulating the first AD sampling data and the second AD sampling data output by the two AD modules respectively to obtain first current data and second current data, and outputting the first current data and the second current data to a current comparison output module; according to the first AD sampling data and the second AD sampling data, fault judgment is carried out on the two AD modules, and a step wave signal is generated according to the fault-free current data; generating a bias signal according to the eigenperiod of the optical path; superposing the step wave signal and the bias signal, converting the signals into analog signals through DA, and feeding the analog signals back to a Y waveguide modulator of the optical fiber current transformer to realize closed-loop control;
the current comparison output module outputs the first current data and the second current data; the two paths of data are all acquired from the same photoelectric detector, under the condition that the AD data comparison module judges that no fault exists in the two paths of AD, the difference between the two paths of demodulation current data is not large, and the difference between the demodulation current data is not larger than a set threshold, so that the module compares the first current data with the second current data respectively, when the difference between the first current data and the second current data is larger than a preset second threshold, a fault alarm signal of the data processing module is output, the current data abnormity caused by the damage of key devices of the device is prevented, the protection misoperation is caused, if the data are normal, the two paths of current data are sent according to a communication protocol specified by a user, and the dual configuration requirement is finally realized. The module is preferably realized by a single chip device. The second threshold is less than 1% of the first current data or the second current data.
The data processing module is a circuit core part, and is used for judging data and giving alarm information by controlling AD sampling and DA offset in a time sequence manner; and parallel data demodulation is carried out, bias waveform application and step wave feedback closed-loop control are controlled, functions of double sampling, double output, fault alarm and the like are realized, and the requirement of power engineering application dual configuration is met.
The data processing module is realized by adopting a programmable logic device and a data processing algorithm, the principle mechanism is shown in fig. 3, the data demodulation module comprises a time sequence control module, an AD data comparison module, a demodulation module, a bias modulation wave generation module, a step wave generation module, a signal superposition module and a DA conversion module, wherein:
and the time sequence control module generates two working clocks of the AD module and the DA conversion module according to the intrinsic cycle of the light path, controls the working and running time sequences of the AD and DA devices, ensures that two paths of AD are used for alternately sampling the photoelectric detector signals in the same modulation amplitude after the DA applies a bias signal, and ensures that two paths of sampling values are synchronous. The double-AD sampling and DA offset modulation time sequence is shown in fig. 2, after the offset waveform is applied to the DA, the AD1 and the AD2 acquire electric signals of the photoelectric detector in parallel in the same modulation amplitude, and in order to avoid mutual influence of two AD samplings, AD1 and AD2 sampling pulses are performed at crossed intervals, so that sampling influence is avoided, and the fact that the size of sampling data in the same modulation copy is close enough is guaranteed.
The AD data comparison module is used for judging faults of the two AD modules according to the first AD sampling data and the second AD sampling data, when the difference between the accumulated average values of the first AD sampling data and the second AD sampling data in the same modulation amplitude exceeds a preset first threshold value, one of the AD modules is considered to have faults, and otherwise, both the two AD modules are considered to have no faults; when the accumulated average value of the sampled data obtained by the same AD module in the same modulation amplitude value is in a preset reasonable range, the AD module is considered to have a fault, otherwise, the AD module is considered to be normal, and an AD module fault alarm signal is sent out; the first threshold value mainly considers the sampling difference in the same modulation amplitude, and as the sampling is the same detector signal, the sampling clock interval is alternately performed, the sampling data are close enough, the difference between the two AD chips is small, and the sampling is close, the first threshold value is generally set to be 20 LSB. The difference between normal sampling and fault sampling in AD work is considered mainly in the preset reasonable range, the reasonable range is a normal sampling experience value which is a sampling average value when the AD works normally, and application thresholds of different products are different.
The demodulation module is used for carrying out parallel processing on the two paths of AD sampling data, independently demodulating the two paths of AD sampling data to obtain first current data and second current data, outputting the current data obtained by adding and averaging the first current data and the second current data to the step wave generation module when the two AD modules have no fault, and outputting the current data to the step wave generation module according to the current data output by the normal AD module when the one AD module has a fault;
the step wave generating module is used for generating a step wave signal according to the current signal input by the demodulation module;
the bias modulation wave generating module generates a bias signal according to the intrinsic cycle of the light path; the bias signal is a square wave, a four-state wave or a random four-state wave, the value range of a bias point is pi/2-pi 3/4, and the proper bias point is selected to be beneficial to improving the test linearity and sensitivity.
The signal superposition module is used for superposing the bias signal and the step wave signal to obtain a feedback signal and outputting the feedback signal to the DA conversion module;
and the DA conversion module is used for DA converting the feedback signal and applying the DA converted feedback signal to a Y waveguide modulator of the optical fiber current transformer to form closed-loop control.
A double-sampling double-demodulation fault warning method for an optical fiber current transformer is characterized by comprising the following steps:
(1) sampling signals output by the photoelectric detector of the optical fiber current transformer by adopting two independent AD sampling modules to obtain first AD sampling data and second AD sampling data;
(2) judging faults of the two AD modules according to the first AD sampling data and the second AD sampling data, and when the difference between the accumulated average values of the first AD sampling data and the second AD sampling data in the same modulation amplitude exceeds a preset first threshold value, judging that one AD module has faults, otherwise, judging that both the two AD modules have no faults; when the accumulated average value of the sampled data obtained by the same AD module in the same modulation amplitude value is in a preset reasonable range, the AD module is considered to have a fault, otherwise, the AD module is considered to be normal; when both the two AD modules have no fault, generating a step wave signal according to current data obtained by adding and averaging the first current data and the second current data, when one AD module has a fault, generating a step wave signal according to current data output by a normal AD module, and otherwise, generating a step wave signal according to current data of the intrinsic period of the previous light path.
(3) Generating a bias signal according to the intrinsic cycle of the optical path, and entering the step (4);
(4) superposing the step wave signal and the bias signal, converting the signals into analog signals through a DA conversion module, and feeding the analog signals back to a Y waveguide modulator of the optical fiber current transformer;
(5) and outputting the first current data and the second current data, simultaneously comparing the first current data with the second current data respectively, and outputting a data demodulation module fault alarm signal when the difference between the first current data and the second current data exceeds a preset second threshold value.
In summary, the device and the method of the invention can realize the functions of double sampling and double demodulation, closed loop modulation, AD sampling fault alarm, data processing module fault alarm and the like on the same current transformer light path. The scheme of the invention has the advantages of simple structure, low cost and high intelligent degree.
Those skilled in the art will appreciate that those matters not described in detail in the present specification are well known in the art.
Claims (6)
1. The utility model provides a two demodulation fault alarm device of double sampling for fiber current transformer which characterized in that: including two AD modules, data processing module, electric current contrast output module, wherein:
the two AD modules independently sample voltage signals output by the photoelectric detector of the optical fiber current transformer under the control of a sampling clock to obtain first AD sampling data and second AD sampling data, and output the first AD sampling data and the second AD sampling data to the data processing module;
the data processing module generates a clock signal and sends the clock signal to the AD module and the DA conversion module; according to the intrinsic cycle of the light path, demodulating the first AD sampling data and the second AD sampling data output by the two AD modules respectively to obtain first current data and second current data, and outputting the first current data and the second current data to a current comparison output module; according to the first AD sampling data and the second AD sampling data, fault judgment is carried out on the two AD modules, and a step wave signal is generated according to the fault-free current data; generating a bias signal according to the eigenperiod of the optical path; superposing the step wave signal and the bias signal, converting the signals into analog signals through DA, and feeding the analog signals back to a Y waveguide modulator of the optical fiber current transformer to realize closed-loop control;
the current comparison output module outputs the first current data and the second current data; meanwhile, the first current data and the second current data are compared respectively, and when the difference between the first current data and the second current data exceeds a preset second threshold value, a fault warning signal of the data processing module is output;
the data processing module comprises a time sequence control module, an AD data comparison module, a demodulation module, a bias modulation wave generation module, a step wave generation module, a signal superposition module and a DA conversion module, wherein:
the time sequence control module generates two working clocks of the AD module and the DA conversion module according to the intrinsic period of the light path and controls the working operation time sequence of the AD device and the DA device;
the AD data comparison module is used for judging faults of the two AD modules according to the first AD sampling data and the second AD sampling data, when the difference between the accumulated average values of the first AD sampling data and the second AD sampling data in the same modulation amplitude exceeds a preset first threshold value, one of the AD modules is considered to have faults, and otherwise, both the two AD modules are considered to have no faults; when the accumulated average value of the sampled data obtained by the same AD module in the same modulation amplitude value is in a preset reasonable range, the AD module is considered to be normal, otherwise, the AD module is considered to have a fault, and an AD module fault alarm signal is sent out;
the demodulation module is used for carrying out parallel processing on the two paths of AD sampling data, independently demodulating the two paths of AD sampling data to obtain first current data and second current data, outputting the current data obtained by adding and averaging the first current data and the second current data to the step wave generation module when the two AD modules have no fault, and outputting the current data to the step wave generation module according to the current data output by the normal AD module when the one AD module has a fault;
the step wave generating module is used for generating a step wave signal according to the current signal input by the demodulation module;
the bias modulation wave generating module generates a bias signal according to the intrinsic cycle of the light path;
the signal superposition module is used for superposing the bias signal and the step wave signal to obtain a feedback signal and outputting the feedback signal to the DA conversion module;
and the DA conversion module is used for DA converting the feedback signal and applying the DA converted feedback signal to a Y waveguide modulator of the optical fiber current transformer to form closed-loop control.
2. The double-sampling double-demodulation fault warning device for the fiber current transformer according to claim 1, characterized in that: the bias signal is a square wave, a four-state wave or a random four-state wave.
3. The double-sampling double-demodulation fault warning device for the fiber current transformer according to claim 1, characterized in that: the bias point of the bias signal has a value range of pi/2-pi 3/4.
4. The double-sampling double-demodulation fault warning device for the fiber current transformer according to claim 1, characterized in that: and in the same modulation amplitude of the optical fiber current transformer, the two AD modules alternately sample at intervals.
5. The double-sampling double-demodulation fault warning device for the fiber current transformer according to claim 1, characterized in that: the data processing module is realized by adopting a programmable logic device.
6. A double-sampling double-demodulation fault warning method for an optical fiber current transformer is realized by adopting the device of any one of claims 1 to 5, and is characterized by comprising the following steps:
(1) sampling signals output by the photoelectric detector of the optical fiber current transformer by adopting two independent AD modules to obtain first AD sampling data and second AD sampling data;
(2) judging faults of the two AD modules according to the first AD sampling data and the second AD sampling data, and when the difference between the accumulated average values of the first AD sampling data and the second AD sampling data in the same modulation amplitude exceeds a preset first threshold value, judging that one AD module has faults, otherwise, judging that both the two AD modules have no faults; when the accumulated average value of the sampled data obtained by the same AD module in the same modulation amplitude value is in a preset reasonable range, the AD module is considered to be normal, otherwise, the AD module is considered to have a fault; when both the two AD modules have no fault, generating a step wave signal according to current data obtained by adding and averaging the first current data and the second current data, when one AD module has a fault, generating a step wave signal according to current data output by a normal AD module, or else, generating a step wave signal according to current data of the intrinsic period of the previous optical path;
(3) generating a bias signal according to the intrinsic cycle of the optical path, and entering the step (4);
(4) superposing the step wave signal and the bias signal, converting the signals into analog signals through a DA conversion module, and feeding the analog signals back to a Y waveguide modulator of the optical fiber current transformer;
(5) and outputting the first current data and the second current data, simultaneously comparing the first current data with the second current data respectively, and outputting a data demodulation module fault alarm signal when the difference between the first current data and the second current data exceeds a preset second threshold value.
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| CN109143066B (en) * | 2018-09-04 | 2021-01-08 | 阳光电源（上海）有限公司 | Motor controller and sampling signal processing method thereof |
| CN109752684B (en) * | 2018-12-25 | 2021-06-11 | 北京航天时代光电科技有限公司 | Photoelectric module reverse testing method and fault diagnosis and judgment method |
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